Certificate of correction



Patented May 24, 1932 OFFICE EDWARD W. ISOM, 0F SCARSDALE, NEW YORK, ASSIGN OR TO SINCLAIR REFIN IN G COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE MANUFACTURING OF LUBRIGATING- OIL No Drawing.

This invention relates to improvements in the manufacturing and refining of lubricating oil. The invention relates more particularly to an improved method of treating inferior grades of lubricating oil or petroleum oil fractions from which lubricating oils are to be obtained for the production of an improved lubricating oil product therefrom. This application is in part a continuation of application 709,682 filed April 28, 1924-.

According to the present invention lubricating oils of inferior grade and low viscosity or petroleum oil fractions from which lubricating oils are to be obtained are subjected I to a digesting treatment at elevated temperatures and pressures to produce an improved lubricating oil of higher viscosity and good lubricating properties.

In the refining of petroleum oil for the production of lubricating oil therefrom, the oil is commonly subjected to distillation with steam or under a reduced vapor pressure, subatmospheric, in order to avoid any possibility of cracking of the lubricating oil constituents, and it is generally accepted that a lubricating oil or a distillate from which a lubricating oil is to be produced should not be subjected to cracking temperatures and pressures, if a lubricating oil of good lubricating properties is to be obtained.

In some cases the oils from which the lubricating oils are to be' obtained are-subjected to a treatment to facilitate the removal of wax, but hitherto such treatment has been confined to such treatment of the 'Wax as would convert it to a so-called crystalline form and the use of temperatures and pressures that might produce cracking of the lubricating oil constituents has been carefully avoided.

As distinguished from such commonly prac ticed refining methods, the process of the present invention involves the digestion of the lubricating oil constituents at high tempera tures and pressures. The reaction is appar- Application filed June 6, 1927. Serial No. 197,011.

ently a cracking of the heavy oils and a recombining of the condensates of unsaturated constituents to form heavier hydrocarbons and a very small proportion of lighter hydrocarbons.

The lubricating oil or distillate may be subjected to the digesting treatment prior to removal of wax therefrom or the wax may be first removed in the crystalline form by pressing or in the amorphous form by centrifuging or cold settling, and the-wax free oil subsequently subjected to the digestion treatment. Where the digestion treatment is carried out prior to the removal of Wax substantially no conversion of the crystalline wax into lubricating oil character constituents occurs,

though a considerable increase in the viscous bodies formed by the conversion of the remainder of the oil may be noted. It is accordingly preferable to remove the wax prior to the digestion treatment because of 1 the tendency of these constituents to undergo cracking with the formation of low viscosity and low boiling point constituents at the temperatures employed and the greater difficulty encountered in the separation of the unconverted Wax from the more viscous oil formed during the digestion treatment. Following the digestion treatment the treated oil may be reduced by fractional distillation with or Without steam or at reduced pressure to give a product having the viscosity and flash point of the desired lubricating oil product and to remove the small quantity of lighter constituents formed during the digesting operation.

The temperature to which the oil is heated, as well as the length of time during which the temperature and pressure are maintained, will vary somewhat with different oils and with the characteristics of the product it is desired to produce. In general,the higher the temperature and the greater the length of time, within certain limits, the greater the proportion of viscous bodies formed.

The oil which has been subjected to the dithe more unstable,

and withdrawing the sludge gesting operation may advantageously be given a suitable chemical treatment, for example, agitation with sulphuric acid, settling formed followed by neutralization with lye or treatment with an absorbent or filtering material, to remove unsaturated constituents and heavy asphaltic constituents contained in the oil treated or formed during the digesting operation. In the treatment of an oil containing a large percentage of asphaltic constituents the digesting operation may be preceded by treatment with sulphuric acid. When the desired lubricating oil fraction which has been subjected to the digesting operation is to be obtained as an overhead istillate from a subsequent fractional distilla tion, such subsequent distillation may advantageously be carried out over lye, the asphaltic bodies being held with the lye and a clean oil resulting.

According to one method of carrying out the process of the invention an oil containing constituents suitable as components of a lubricating fraction, for example, pressed distillate from which the crystalline wax has been removed, raw wax distillate, reduced crude, or a practically finished low viscosity lubricating oil is placed in an autoclave and gradually heated to a temperature of about 64:0 to 7 90 degrees F. and maintained at that temperature for the requisite period. The pressure may advantageously be maintained at from 125 lbs. to 200 lbs. per square inch. The pressure in any event is maintained sufficiently high to prevent substantial vaporization.

When the oil to be treated contains a small percentage of lighter constituents the use of excessive pressures may be avoided by taking oft these lighter constituents as drips while the autoclave is being brought to the desired temperature. Similarly, the pressure may be prevented from increasing excessively during the digesting operation, due to the formation of a small quantity of low boiling constituents, by taking oil drips at intervals during the digesting operation.

The time during which the temperature and pressure conditions necessary for the conversion of the lighter constituents to tained will vary with the gree of conversion peratures employed, a longer time being required to secure the same amount of conversion at a lower temperature. From 4 to 12 hours has been found to give very satisfactory results though a slight amount of additional conversion may tinui'ng the digesting operationfor a somewhat longer period. Tests in which the digesting treatment was continued for 24 hours indicated a slight increase in the yield of ex tremely viscous bodies but a decrease in the be obtained by conrename yield of lubricating distillates of slightly lower viscosity as compared to the yields obtained in a similar treatment of 12 hours duration.

Subsequent to the digesting operation the oil may be given suitable chemical treatment and redistilled or reduced, the final product being used alone or blended with other finished lubricating oils, or the product from the digesting operation may be blended with other unfinished lubricating oil stocks and the mixture subsequently treated as required.

The apparatus that can be used in carrying out the process of the invention varies. An ordinary shell still can be used, provided it is suitably heated so that over-heating of the charge or any part thereof is avoided. A tube still such as is employed in commercial cracking operations for the production of gasoline or pressure distillate from heavy hydrocarbon oils in which oil is circulated through heating tubes, preferably by mechanical circulation so that danger of local overheating of the oil passing through the dee tubes is positively avoided, may also be a vantageously employed.

The process of the invention will be further described in connection with the following specific examples which are given to illustrate the effect of varying temperatures, pressures, character of oil treated and duration of run, but it is intended and will be understood that the process of the invention is merely illustrated thereby and not limited thereto. The viscosities in the following examples are the values as determined by the Sa bolt universal viscosimeter:

ram le 1 .Pressed distillate from a midcontinent crude having a gravity of 28.8 degrees Baum and viscosity of 66 at degrees F. was charged to an autoclave and gradually heated to a temperature of 700 degrees. During the preliminary heating 5% of the charge was taken OK as drips. The autoclave was maintained at a pressure of 180 pounds per square inch for 4 hours during which time the temperature varied from 680 to 790 degrees F. The autoclaved stock was then treated with 10 pounds per barrel of 66 degree Baum sulphuric acid, the sludge settled and withdrawn and the settled oil neutralized with lye. The treated oil was then distilled over lye, the distillate being separated in l% cuts from which various test distillates were made by blending. The fractional distillation was carried down to 5% lye bottoms.

The various test distillates were made by blending fractions from the above distillation, starting with the heaviest cut or fraction and adding successively lighter cuts or fractions until an oil of the desired viscosity was obtained. In obtaining a 100 viscosity of the heaviest distillate was omitted. The

test distillates were blown with steam to remove the odor and then blown bright with air. Raw pressed distillate was similarly fractionated and corresponding test distillates made by blending the fractions obtained.

Results of tests of the samples obtained from the autoclaved stock and from the raw pressed oil are tabulated below in the col 89 at 100 degrees F. was charged to an autoclave and maintained at a pressure of 125 pounds per square inch for 12 hours during which time the temperature varied from 755 degrees F. at the start to 640 degrees F. at the close. 5% of the charge was taken oil as drips at the start of the run.

The autoclaved oil was then treated with 10 pounds per barrel of 66 degree B. sulphuric umns marked A and B respectively: acid, the sludge allowed to settle and with- 100 vis. 180 vis. 235 vis. 285 vis. 500 vis. Grade A B A B A B A B A stock 37. 1 59. 0 32. 7 24. 0 26. I -16. 0 22. 0 -11. 0 l3. 2 Gravity B 24. 0 25. 7 22. 0 23. 9 20. 8 23. 3 19. 8 -22- 9. 19. 3 Flash F 360 -360 375 400 395 405 400 410 425 Fire F 415 420 455 480 465 490 480 -50!) 510 vis./100 F 109 108 186 190 238 235 284 275 499 vis./210 F 40 -40 45 45 47 47 49 28. 5 57 P0111 "F 20 -20 15 20 15 20 15 -20 20 Carbon res 037 016 187 034 185 045 190 O86 45% Sulphur 043 44 49 51 53 54 55 56 57% No fraction comparable to the 500 viscosity drawn and the settled oil neutralized with distillate was obtained from the raw pressed lye. Oll. The autoclaved and acid treated stock was The efiect of lncreasln the length of the fractionally dlstilled leavlng 5% bottoms. digesting period and of ecreasing pressure The distillate was separated into 5% cutsand are illustrated by the following example: these cuts or fractions blended to obtain the Example 2.A pressed 011- from a m1d-condeslred test dlstillates. The test distillates tinent crude having a gravity of 28.6 degrees were given a fine earth treatment to. bring Baum and viscosity of 66 atlOO degrees F. was treated in an autoclave at 125 lbs. pressure for a period of 12 hours during which time the temperature varied between 715 and 750 de rees F., 5% of the charge was taken ofi as d rips during the initial heating period. The autoclaved stock was then treated with 10 lbs. per barrel of 66 degrees Baum sulphuric acid, the sludge settled and with-' drawn and the settled oil neutralized with lye. The autoclaved and acid treated oil was then fractionally distilled over lye and portions of the cuts obtained thereby blended to give the following test distillates which were steamed to remove the odor and then blown taught with a1r:

100 vis. 180 vis. 235 vis. I 285 vis. 500 vis.

%stock 39. 2 36. 7 29. 1 25. 0 15. 2 Gravity 34. 1 21. 8 20. 9 20. 3 18. 5 vis./100 F 108 188 236 284 509 vis./210 F-..-- 40. 0 45. O 47. 0 49. 0 58 Comparison of the test distillates obtained in Examples 1 and 2 lndlcate that a slightly higher yield of viscous constituents was obtained as a result of the longer period of digestion even though at somewhat reduced temperatures and pressures.

Comparison of Examples 3 and 4 which follow illustrates the elfect of excessively prolonging the digestion period.

Ewample 3.A light lubricating oil distillate from a mid-continent crude having a gravity of 26.7 degrees B. and a viscosity of vis., 180 vis., autouto- I 100 vis., a

claved claved blank Fractional distillation of the treated and autoclaved stock and of the original lubricating oil distillate were both continued, until 5% of the charge remained as still bottoms. The viscosities of the heaviest fraction obtained as distillate in each case comprising 5% of the charge were found to be 564 at 100 degrees F. in the distillate from the autoclaved stock as against 181 at 100 degrees F. in the distillate from the blank stock.

Ewa mple 4.A light lubricating oil distillate from a mid-continent crude having a gravity of 28.9 degrees B. and-viscosity of 62.5 at 100 degrees. F. was charged to an autoclave and maintained at a pressure of 125 pounds per square inch for a period of 24 hours during which time the temperature llllll The autoclaved oil .was then treated with 10 pounds per barrel of 66 degree Baum sulphuric acid. The autoclaved and treated oil was then fractionally distilled over lye and the various cuts obtained blended to give test distillates of the desired viscosity. The quantity of the original distillate was reduced to give an oil of approximately 75 viscosity at 100 degrees F. Results of tests on the reduced blank stock and the autoclaved distillates are given below:

75 vis., 75 vis., 100 vis., 180 via, 235 vis., reduced autoautoautoau 0- oil-blank claved claved claved claved stock 60. 0 57. 0 35. 0' 17. 1 10. 7 Gravity 28. 0 35. 4 23. 5 21. 0 20. 0 iS./100 'F 74. 0 75.0 104. 5 185 235 Via/210 F-... 38.0 38.0 40. 0 45 48 The heaviest fraction of the autoclaved oil comprising 5% of thestill charge was found to have a viscosity of 653 at 100 degrees F. while the same fraction from the untreated distillate had a viscosity of only 127 at 100 degrees F. Comparison of the results obtained in Examples 3 and 4 indicates that the longer period of digestion causes the conversion of a small quantity of the original distillate to a higher viscosity oil than that obtained in a digesting operation of shorter duration, but yields a smaller quantity of lubricating oil distillates having but slightly lower viscosities.

The following example illustrates the effect of increased pressure in the treatment of reduced crudes in accordance with the process of the invention and also the eiiect of acid treating the charging stock prior to the digesting operation.

E mample 5.--The charging stock was prepared by reducing a mid-continent crude 53% being taken off as late. The bottoms comprising 46% and having a gravity of 30.3 degrees B. was used as charging stock, 1% being lost as fixed gas.

A. A portion of the reduced crude was charged to an autoclave and maintained at a pressure of 125 pounds for a period of twelve hours-during which time the temperature varied from 660 to 710 degrees F. 8%% of the charge was taken ofi as drips at the start of the run. then treated with 20 pounds per barrel of 66 degree B. sulphuric acid, the sludgesettled and withdrawn and the settled oil neutralized with lye. The autoclaved and acid treated oil was fractionally distilled 76.7% of the still charge being taken off as an overhead distillate. The bottoms comprising 17.6% of the original autoclave charge had a viscosity of 154 at 210 degrees F. and a gravity of 22.0 degreesB. This highly viscous oil was of a very dark green color and gave a an overhead distil-' The autoclaved stock was carbon residue of 6.14% as determined by the Conradson method.

B. A portion of the same charging stock was treated in an autoclave at 200 pounds pressure for 12 hours during which time the temperature was and 750 degrees F. No drips were removed. The autoclaved oil was treated with 20 pounds per barrel of 66 degree B. sulphuric acid, the sludge settled and withdrawn and the settled oil neutralized with lye.

maintained between 640 y autoclaved and acid treated stock was reduced by fractional distillation 73% being taken ofl as overhead distillate. The reduced oil comprising 22.6% of the autoclave charge was of a very dark green color and had a viscosity of 160 at 120 degrees F. and a gravity of 23.6 degrees B. An appreciable increase in the yield of highly viscous oil being obtained as a result of the higher pressure employed during the digesting operation.

0. A quantity of the reduced crude similar to the original autoclave charge in the two preceding pounds per barrel of 66 degree B. sulphuric acid,-the sludge settled and withdrawn and the settled oil neutralized with lye. .The acid treated oil was then charged to an autoclave and heated for 12 hours at a pressure of 125 pounds per square inch during which time the temperature varied between 640 and 710 degrees F. No drips were taken oil. The autoclaved stock was then treated with 15 pounds per barrel of 66 degree B. sulphuric acid and the treated and autoclaved stock reduced by fractional distillation, 77% of the still charge being removed as an overhead distillate; The still bottoms, comprising 19.8% of the original reduced crude charging stock was of a very dark green color having a gravity of 23.9 degrees B. and a viscosity of 146 at 210 degrees F. and showed a carbon residue of 4.128% as method. An appreciable decrease in carbon residue will be noted where the preliminary acid treatment was given prior to the digesting operation.

E wample 6.--A lubricating oil distillate prepared from a Gulf Coast or asphalt base crude was treated in an autoclave at a pressure varying between 180 and 200 pounds per square inch for a period of 4 hours during whichthe temperature varied from 690 to 750 degrees F. No drips were taken ofi. Samples of the autoclaved and raw stocks were treated with 15 pounds per barrel of 66 examples was treated with 10 determined by the Conradson degree B. sulphuricacid and the treated stock finished lubricating oil distillates from the blank and autoclaved stocks are given below:

Auto- Blank claved distillate distillate 9! original lubricating distillate 57. e 47. 4 Gravity Baum 19. 9 l7. 8 We. at 100 F 246 240 28.4 degrees Baum and viscosity of 72 at 100 degrees F. was treated in an autoclave at a pressure of 150 to 170 pounds per square inch for a period of 4 hours during which the temperature varied between 650 and 735 degrees F. The autoclaved stock was treated with 10 pounds per barrel of 66 degree Baum sulphuric acid, the sludge settled and withdrawn and the settled oil neutralized with lye. The autoclaved and acid treated stock and a sample of the original pressed distillate were reduced to obtain lubricating oil fractions of the desired viscosity. Results oftests on the reduced autoclaved stock and on the corresponding fractions from the original pressed distillate are tabulated below in columns A and B,respectively:

mid-continent crude having a gravity of F charge being added as 30 degrees Baum lye. 6.5% of the charge was separately collected as gas oil and 88.5 as red oil stock, 5% remainin in the still as lye bottoms. The red oil stoc was then reduced, 74.9% being removed as an overhead distillate suitable as a light lubricating oil stock and the bottoms comprising 19.2% of the original autoclaved charge, bleached by digestion with 2% by weight of'fine fullers earth of 200 mesh and up. Comparative results of tests on the finished autoclaved oil and on the typical example of Queens Red oil are given below:

Auto- Queens daved red red oil Gravity "B 24. O 21. 3 Flash 430 420 ire 500 505 Via/100 F 379 384 Via/210 F 54 55 Pour 50 20 Color Dark red. Dark red.

Emample a-A raw fwax distillate having a gravity of 30.3 B. and pour of 70 degrees F. was treated in an autoclave for 12 hours at a pressure of 125 pounds and at temperatures varying from 640 to 740 degrees F. 10% of the charge was removed as drips during the fore part of the run to establish constant pressure conditions. The autoclaved product was treated with 12 pounds per barrel of 66 degree B. sulphuric acid, the sludge settled and withdrawn and the settled oil neutralized with lye. The autoclaved and acid treated stock was fractionally distilled over lye, the distillate being separately cuts. The viscosities and pour tests of the various fractions are given Gravity Pour collected in 5% 235vis. 275vis. I 500vjs. below:

A B A B A stock 41.3 26.8 39.0 23.5 22.7 out Gravity 21.7 23.5 21.4 23.2 20.7 Viscosity 267 270 294 800 6 N0 oils, corresponding to the 500 viscosity fraction were obtained by reduction of the original pressed distillate.

Example 8.-To produce a red lubricating oil similar to that Queens Red, the properties of a representative sample of which are 'ven below, by the improved process of t pressed oil from a mid-continent crude was known to the trade as 10 e invention a 15 charged to an autoclave and heated for 12 is The high pour tests of the heavier fractions show that practically no conversion of the crystalline wax into high viscosity, lu-

bricating oils was caused by (the autoclave treatment. A substantial increase in viscous bodies was, however, produced by conversion'of the lighter constituents in the raw distillate as a result of the autoclave treatment.

The improved high viscosity lubricating oils produced by the practice of the invention are characterized by the relatively higher specific gravity (lower Baum gravity) for an oil of a given viscosity. The degree of saturation as indicated by the iodine number is less for the heavier fractions of the autoclave treated stock than for the lighter fractions. This characteristic is the exact reverse of the conditions obtained with pressure treatment where the products of reaction are released as fast as formed. Lubricating oils produced by the improved process of the present invention are also more stable and less readily decomposed at the temperatures encountered in the lubrication of internal combustion engines.

The invention is capable of numerous modifications as will be apparent from the filri ety of the foregoing examples which have been given to illustrate certain preferred applications, but the scope of the invention is set forth in the following claims:

I claim:

1. The improvement in the manufacturing and refining of lubricating oils which comprises subjecting a petroleum oil containing a lubricating oil fraction to a digestion treatment at a temperature of from 640 to 790 derees F. from 4 to 12 hours at the pressure necessary to prevent substantial vaporization of the lubricating oil constituents.

2. The improvement in the manufacturing and refining of lubricating oil which comprises digesting a petroleum oil containing members of the paraffine series suitable as components of lubricating oil at a temperature of 640 to 7 90 degrees F. for from t to 12 hours, and maintaining on the oil during the digesting operation the pressure necessary to prevent substantial vaporization of the lubricating oil constituents to increase the yield of high viscosity lubricating oil constituents.

3. The method of treating petroleum oil containing lubricating oil constituents to increase their viscositv comprising digesting the oil from 4 to 12 hours at temperatures between 640 and 790 degrees F. and at pressures upward of about 125 pounds per square inch and sutlicient to prevent substantial vaporization of the lubrication oil constituents. treating the digested oil with sulphuric acid to remove the more unstable, unsaturated hV- drocarbons and subsequently fractionally distilling the treated oils to obtain the desired. lubricating oil fraction.

4. The method of treating petroleum oils containing lubricating oil constituents to increase their viscosity comprising heating a charge of the oil in an autoclave to a temperature in excess of 640 degrees F. IQIHOV? mg the lighter constituents vaporized during the preliminary operation to establish constant pressure conditions and maintaining a temperature between 640 to 790 degrees F. and the pressure necessary to prevent substantial vaporization of the lubricating oil constituents at the temperature employed for a period of 4; to 12 hours on the remainder of the charge and subsequently treating the digested oil to remove therefrom the lighter oils and the more unstable unsaturated constituents formed during the digesting operation.

5. The improvement in the manufacturing and refining of lubricating oils which comprises subjecting a petroleum oil containing a lubricating oil fraction to a digestion treatment for from 4 to 24 hours at a temperature of from 640 to 790 F. and a pressure upwards of about 125 pounds and sufficient to prevent substantial vaporization of the lubricating oil fraction.

6. The improvement in the manufacturing and refining of lubricating oils which comprises treating a petroleum oil containing constituents suitable as components of a lubricating oil fraction to remove the wax contained therein and subsequently digesting the wax-free oil from a to 2d hours at temperatures between 640 to 7 90 F. under the pressure necessary to prevent substantial vaporization of the lubricating oil constituents to increase their viscosity.

7 The improvement in the manufacturing and refining of'lubricating oils which comprises subjecting a petroleum oil containing a lubricating oil fraction to a digestion treatment for from 4 to 24: hours at a temperature of from 640 to 790 F. at the pressure necessary to prevent substantial vaporization of the lubricating oil constituents treating the digested oil with sulphuric acid and subsequently distilling the treated oil over lye.

8. The improvement in the manufacturing and refining of lubricating oils which comprises treating an oil containing lubricating oil constituents with sulphuric acid and subsequently digesting the treated oil for from 4 to 24: hours at a temperature of 640 to 7 90 F. at the pressure necessary to prevent substantial vaporization of the lubricating oil constituents.

In witness whereof, l have subscribed my name.

' EDWARD W. llSOll/ll.

CERTIFICATE OF CORRECTION.

Patent No. 1,859,514. May 24, '1932.

EDWARD w. ISOM.

It is hereby certified that error appears in ,the'printed specification of the above numbered patent requiring correction as follows: Page '4, line 82. for the numeral "120" read 210; and that the said Letters Patent should be read with the Patent Office. 4

Signed and sealed this 12th day of July, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

